Eudragit L-100固定球毛壳霉菌木聚糖酶酶学性质的研究

采用可逆溶解性聚合物Eudragit L-100对球毛壳菌木聚糖酶进行了吸附固定化。在1．0％Eudragit L-100浓度时获得10．6IU／mg载体的固定化酶活和88．47％的酶活回收。酶固定化后最适温度不变，最适pH向碱性方向移动了一个pH单位。固定化酶热稳定性和操作稳定性显著提高，循环利用6次仍保留65％初始酶活。木聚糖水解产物测定表明，在同酶用量的条件下固定化后总还原糖产量明显高于游离酶，二者水解产物均以低聚糖为主，酶固定化后水解产物木二糖含量显著高于游离酶，成为主要的产物。木聚糖酶固定化后各方面特性明显优于游离酶，在低聚糖生产中有实际应用价值。

Properties of Xylanase Immobilized on Polymer Eudragit L-100

Eudragit L-100, a reversibly soluble-insoluble polymer, was used for immobilization of xylanase of Chaetomium globosum for production of xylooligosaccharide. The immobilization was performed by a simple adsorption process. The maximum activity 10.6 IU/mg is obtained with 88.47% activity recovery at 1.0% polymer concentration. The optimum pH value increases one unit and the optimum temperature remains unchanged. The immobilized enzyme obviously enhances the thermal stability, and retains 65% of its initial activity after being hydrolyzed repeatedly xylan for six times. Moreover, the time course of hydrolysis of xylan by free enzyme as well as immobilized enzyme was also studied. Due to immobilization, the enzyme produces more reducing sugar than the free enzyme after being hydrolyzed for 24 hours. HPLC analysis indicated that xylobiose and xylotdose are both the immobilized end products with higher content of xylobiose than the free enzyme, whereas the xylobiose has become the major component instead of xylotriose after being immobilized. The enhanced characteristics of xylanase upon being immobilized may be helpful for the application of preparing xylooligosaccharide.